You will likely need to access the Windows API - these posts may help you:

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=114198&SiteID=1
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wmisdk/wmi/wmi_tasks__networking.asp

The second edition of the Pickaxe book has some info on calling the 
Win32API on page 755.

The same example is on the web here:
http://www.rubycentral.com/book/lib_windows.html


Les